SARS-CoV-2 exposure in wild white-tailed deer

https://www.biorxiv.org/content/10.1101/2021.07.29.454326v1.full

by dthal • 5 years ago

19 8 5 years ago

biorxiv.org

platz• 5 years ago

A new animal reservoir for covid

criticaltinker3• 5 years ago

FWIW here is an FAQ from the USDA/APHIS [1], which has some relevant clarifications pertaining to the paper:

- "Could the deer spread the virus to people? There is no evidence that animals, including deer, are playing a significant role in the spread of SARS-CoV-2 to people."

- "Do deer show clinical signs of illness? This was not the focus of our study. However, there were no reports of clinical illness associated with SARS-CoV-2 in the deer populations we surveyed, and clinical signs of SARS-CoV-2 have not been observed in wild white-tailed deer. In addition, captive deer experimentally infected with SARS-CoV-2 as part of a USDA Agricultural Research Service study did not show clinical signs of illness."

[1] https://www.aphis.usda.gov/animal_health/one_health/download...

dredmorbius2• 5 years ago

Unfortunately, in the world of emerging risks, it's not sufficient to base decisionmaking merely off of evidence, though that comes with some nuance.

If there is strong evidence that some phenomena cannot occur (e.g., that there's an inherent barrier to deer-to-deer or deer-to-human transmission), then any further human risk is slight. If however there's merely a lack of evidence of various forms of transmission, then we can't be assured that there is no such transmission. (This was the case with airborne-transmission of COVID-19, early in the pandemic, where "no evidence" was broadly interpreted as "not possible", incorrectly as it turned out.)

I'll also note that the lack of symptomatic illness among deer does not mean that the virus doesn't spread and propagate within and from the deer population.

dredmorbius2• 5 years ago

That was my first thought. The implications:

- The disease is likely to persist even if eradicated in humans.

- The disease will continue to mutate and evolve in this (and potentially other) animal populations.

- If North American wildlife are acquiring SARS-COV-2, then animal populations elsewhere are all but certainly doing so as well.

criticaltinker3• 5 years ago

I find these observations both fascinating & concerning - it represents another subtle but important dimension to consider in our ongoing efforts to mitigate the pandemic.

Although not specifically mentioned in the paper, IMO farms and home gardens are a likely place for such pathogens to be exchanged.

Highlights from the paper (which is not peer-reviewed yet):

- "We evaluated 624 pre- and post-pandemic serum samples from wild deer from four U.S. states for SARS-CoV-2 exposure."

- "Antibodies were detected in 152 samples (40%) from 2021 using a surrogate virus neutralization test."

- "Seroprevalence for individual counties was highly clustered with nearly half of the 32 counties sampled showing no evidence of SARS-CoV-2 exposure"

- "Several potential transmission routes are possible for movement of this virus into wild deer populations. [..] including captive cervid operations, field research, conservation work, wildlife tourism, wildlife rehabilitation, supplemental feeding, and hunting."

- "Wildlife contact with contaminated water sources has also been offered as a potential transmission route, although transmissibility of SARS-CoV-2 from wastewater has yet to be conclusively demonstrated. Transmission from fomites or other infected animal species cannot be discounted."

- "Besides health impacts to wildlife, persistent infections in a novel host could lead to adaptation, strain evolution, and re-emergence of strains with altered transmissibility, pathogenicity, and vaccine escape."

kvonhorn• 5 years ago

IMO farms and home gardens are a likely place for such pathogens to be exchanged

I'm more concerned about wastewater treatment plants

throwawaysea• 5 years ago

There have been past examples of animals in zoos, most recently tigers in Indonesia, also catching COVID-19 (https://abcnews.go.com/Health/wireStory/rare-sumatran-tigers...). However it is scarier to see wild animals carry COVID, especially at such high rates. Have there been examples of past viruses that transmitted from humans to animals, mutated, and then spread back to humans? What I wonder is if a much larger number of hosts exchanging the virus means a higher probability of a dangerous mutation whose evolutionary fitness is adequate to compete against even the Delta (India) variant.

SARS-CoV-2 exposure in wild white-tailed deer

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